Rotary drum filter



vJan. 9,1940. v W,I P,l GEE '2,186,289

' gown Dnra FILTER Filei June' 4,- ,1937

WILLIAM. PRQvlNE GEE "wl-:mola

l BY @AWK ATTORNEY Planted Jan. 9, 1940 UNITED srArss ROTARY DRUM FILTER William P. Gee, Plainfield, N. J., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application June 4, 1937, Serial No. 148,358

14Claima.

This invention relates to a rotary drum lter, and particularly a filter of this character adapted for the continuous dewaxing of mineral oil.

Oneof the principal objects of the invention is to provide a rotary drum filter with means for readily and easily adjusting the extent and degree of vacuum or pressure differential of the cake forming and/or the cake washing and drym ing portions of the cycle.

` Another object of the invention is to provide a iilter of this character having provisions for blocking of! all or any selected part' of the cake forming and/or cake washing and 4drying portions 16 of the cycle by a simple manipulation from the exterior of the filter without dismantling the same. Still another object of the invention is to provide a filter of this character with means for adjusting the location, or the beginning and endv ing, of the'cake forming-and other portions of the cycle, and additional means independent of said adjusting. means for readily varying the extent and the degree `of vacuum or pressure diiferential of anyportion of the cycle.

Other objects and advantages of the invention will be apparent from the following description, the appended claims, and the accompanying drawing. In the drawing, which illustrates preferred embodiments of the present invention, Fig. 1 is a front elevation of a rotary drum filter of the present invention:

Fig. 2 is an end elevation of the face plate at the left-hand end of the journal of Fig. l, looking in the direction of the arrows 2-2 of Fig. 1, with the upper portion of the face plate broken away to show in' elevation the valve plate immediately behind this face plate;

Fig. 3 is a vertical sectional view taken on the plane of the line 3-3 of Fig. 2 illustrating the construction of the valve and face plates and showing an adjustable plug with operating shaft therefor; and

Fig. 4 is a vertical sectional view similar to 5 Fig. 3, showing a modi-lied form of adjustable plug and operating shaft therefor.

Referring to the drawing, the fllter'comprises a journal I0 mounted in bearings II, the journal passing through a sleeve and stuiling box I2 at each endof a vat or tank I3 provided with an enclosing cover `or hood Il. Mounted within the vat I3and carried by the journal IIIv to rotate therewith is the lter drum I E, which may be of entirely conventional construction as is commercially used in rotary drum iilters of this type. 4The filter drum is. partially submerged within the slurry to be filtered which is confined within the tank orvat I3, the periphery of the drum I5 forming the lter surface. This periphery is en built up of a number of segments 4running-.longitudinally of the drum, these segments being separated by suitable spacers or partitions so as to provide a large number of separate illter chambers or zones about the periphery of the lter. Each of these separate chambers is connected by 5 a pipe extending from the chamber down into the hollow journal I0 and then running longitudinally through the journal to a valve plate I6, and against which abuts a stationary face plate I1. One of these pipes is indicated in Fig. 3 at 2i), the pipe connecting with and being fastened within an opening 2i in the valve plate I5 fastened to and rotating with the journal III. In the particular i'llter illustrated, thereare 30 segments or longitudinal filter chambers formed about the periphery of the drum, and consequently 30 pipes extending through the hollow journal I0 and connecting with appropriate pipe openings 2| in the valve plate i6. As shown, the valve plate is constructed of an 2 outer annular plate 22, an inner circular offset plate 23 and a connecting ring 23a. The face plate` I1 is held tightly against the valve plate by means ci suitable tie rods and springs 24 (Figs. 1 and 2)l which fasten in lugs in bearing 25 II. The face plate is made up of a circular piece 26 carrying inwardly projecting flanges 26 and 21 forming an annular chamber 23 between the valve plate and face plate. The ends of flanges 26 and 21 abut against a suitable wear plate 29 30 fastened to piece 22 of the valve plate I6 and formed with openings aligning with the pipe openings 2|. The valve plate I6 also carries a sleeve bearing. 30 arranged tovreceive the sliding `contact of ange 26 of the face plate I1. The 35 wear plate 23 and the sleeve bearing 30 thus receive the sliding engagement between the rotary valve plate and the stationary face plate. The valve plate is provided with a lower suction connection or filtrate discharge 32 communicating 40 with annular chamber 28, and an upper suction connection or wash filtrate discharge 33 alsso communicating with' the annular chamber In accordance with the present invention, the 45 face plate I1 carries a plurality of adjustable plugs 35, each mounted on the threaded end of an adjustable valve stern 36 passing through a stumng box 31 in the face of plate 25. By turn-l ing valve stem 36, the plug or valve 35 shown in 50 Fig. 3 as abutting-against the wear plate 29 and consequently closing port 2I of one of the pipes 20, will be moved to the right along threads of the valve stem, and thereby open communication between pipe 20 and chamber 23 including suc- 5l tion outlet 32. Valve stem 36 is threaded so that the plug 35 can be moved to the right in Fig. 3 until it abuts against the inner face of plate 2l. Each plug 35 is trapezoidal in shape in front ele Vation as indicated in 2, the sides of the plug 'up or cake forming groove 'engagement with flanges 26 and 21. As shown, iiange 26 is provided with grooves 50, and

4flange 21 with grooves 5|, the plugs carrying tongues at opposite ends thereof which ride within said grooves. Each plug is machined to slidably engage adjacent plugs on opposite sides thereof as indicated in Fig. 2, or a slight clearance may be provided therebetween. Each plug 3b is also constructed of a thickness (as shown in Fig. 3) less than half the width of the chamber 2d, considered as extending from the inner wall of plate 25 to the opposite wall-of wear plate 2t. This means that,y when one plug 35 is completely closed by .abutting against wear plate 29 and shutting off the corresponding opening 2l of the respective pipe 20, while adjacent plugs on opposite sides thereof. are completely open (i. e., abutting against the inner face of plate 25), a communicating space will be provided in the annular chamber 23 around the closed plug 35. This enables any portion of the plugs 35 to be closed, and yet those plugs which are open still aordcommunication of their respective pipes 20 with the discharge suction outlets 32 or 33. y

As'shown, an adjustable plug 35 is provided for each pipe 20, except for a permanently positioned plug 42 mounted between anges 26 and 21 and covering an extent equivalent to three pipe openings 2i, thereby controlling three segments of the ilter. This permanently positioned plug 42 is provided with a circular bore or hole 43 extending through and adapted to register with each pipe opening 2l as it rotates past this bore 43. Connected to the outer end of this bore d3 is a pressure blow-back connection 44 (Fig. 1) adapted to supply a blow-back gas to discharge the` niter cake from the filter surface of the drum l5 into a suitable trough 45, in which operates a feeding screw d6 which continuously discharges the cake through discharge spout 41. Face plate l1 is also provided with lugs 48 having elongated arcuate slots 49 receiving the tie rods 24, so that the plate can be rotated through a slight angle when the tie rods 24 are loosened, thereby permitting adjustment of the location, that is, the beginning and ending, of the cake forming, cake glashing and drying, and discharge zones of the ter.

In the operation of the lter on dewaxing of mineral oil, tank i3 is partially lled withvchilled wax slurry to be iiltered until the rotary drum l5 is substantially half submerged. Suction is provided on connections 32v and 33 leading respectively to oil filtrate and wash nitrate receiving tanks, or the interior of thrllter' casing with enclosing hood ld may be illled with a gas under pressure, so as to give either continuous vacuum or continuous pressur lter operation. The submerged -portion of the iilter constitutes the pickportion of the'cycle.. Assuming all the plugs 35 of this cake forming portion of the cycle to be suction will be produced in the pipes 2Il as they rotate past this portion, such vacuum being communicated to the'lter chambers. This will cause oil filtrate to pass through the periphery oi drum I5 into the filter chambers and thence through Pipes 23 to discharge outlet 32, while a wax cake will be built up on the iilter surface.

As the iilter with wax cake continues to rotate in the direction of the arrow 40 in Fig. 2, the nlter niriace with wax cake thereon emerse open, then a high degree of from the wax slurry. The wax cake is then washed with chilled wash solvent byk suitable means (not shown) and further dried by drawing gas from the gaseous atmosphere within the closed hood oi'. the filter casing through the cake `by suction applied through outlet 33. if a different suction is desired in the cake washing and drying zone from that applied in the pickup or cake forming zone, then one or more of the plugs 35 positioned approximately at the zone'where the filter emerges from the-wax slurry are closed. other adjacent plugs being left partially open so as to effectively close communication between that lower part of annular chamber 28 which is within the cake forming zone and that upper part of chamber 2B which is within the cake Washing and drying zone. As the filter continues to rotate past the cake drying zone, it then comes opposite the permanently positioned plug 42, where the cake is discharged by blowback gas, assisted if. desired by a suitable deector blade or scraper (not shown). The permanently positioned plug closes communication between the right-hand portion of the annular chamber 28 within the cake washing and drying zone and theadjacent end of the chamber 28 within the cake forming zone where the pickup starts. As the lter continues to rotate past the permanently positioned plug 42, the

ports 2l of pipes 20 again come opposite open plugs within the cake forming zone, and the cycle is repeated.

In the conventional rotary drum lter, the stationary face plate is generally provided with three separate annular zones or chambers opposite the pipe openings of the rotary valve plate. y One of these annular chambers arranged at the bottom controls the pickup portion of the cycle, the

second annular chamber controls the cake washwhich can be applied in the pickup zone or in the cake washing and drying zone. Adjustment cycle, and the third of the face plate through the medium oi lugs 48 and tie rods 24 merely alters the location of the various zones slightly, but does not afford any control of the extent or duration of the active portion of those zones.'

ApplicationA of the continuous drum lter to mineral oil dewaxing has involved apparently unique problems, due to the fact that diiierent oil stocks require entirely different iiltration cycles. It has been found desirable to build up a wax cake oi suiilcient thickness for effective removal from the lter, which thickness should not ordinarily be greater than one-quarter inch so as to maintain desirable filtration rates; Certain oil lstocks have free filtering characteristics and build upa wax cake of the desired thickness rapidly. These stocks require a low vacuum dur- "paratively long time to thoroushly washand reaisance tion where cracking tends to occur, which vacuum is just sufficient to retain the cake surface.

Attempts have been made to overcome these problems by dismantling the iilter face plate and inserting plugs in the annular groove or chambers so as to block off a portion of the cake forming time or a portion of the cake washing and drying time. For example, it has been found necessary in some instances to block oi as much as 80% of the cake forming section, while still retaining full vacuum and full extent of the cake Washing and drying time. Attempts have also been made to overcome cake cracking by similarly dismantling the iilter face plate and inserting blocks in the corresponding annular chambers, which blocks are provided with a score or a small groove on the i'ace of the block so that only a low degree of vacuum will be comon the' filter 'municated through the score or groove to the iilter chamber at the location of incipient cracking. Eachtime a different oil stockis dewaxed on the filter which requires a different illtration cycle. the filter valve must be thus dismantled and the blocking changed to meet the new conditions. After the valve is reassembled, it can not be denitely determined, 'until the illteris 'in operation, whether the blocks have been inserted in the proper positions to meet the new conditions. The dismantling or the filter valve of the large rotary drum iilters now employed in commercial dewaxing is an arduous and time consuming task, generally requiring that the filter must be down and out oi production for a day or more, with a consequent very serious loss in production, not to mention the time and labor required in making the change.

The present invention effectively overcomes these difllculties and enables all or any part of the cake forming or cake washing and drying portions of the cycle, or both portions, to be rapidly and easily blocked ofl.' or opened without dismantling of the filter valve and without stopping production. The adjustment of each individual block or plug is readily made by simple manipulation of a wrench applied to the end of valve stem 3B which protrudes to the exterior of the face plate at an easily accessible location. A suitable indicatory (not shown) may be provided for each valve stem of the form shown in Fig. 3, which indicator is responsive to rotation of valve stem 35, so as to indicate to the operator the exact position of the corresponding plug 35. VIn the form shown in \Fig.,3, the valve stem is .iournaled within the plate and is of the nonrising type. Not only' may the extent or active portion of the cake forming and cake washing and drying zones be regulated, but the degree of vacuum or pressure differential at any particular location thereof may be adjusted. Thus one or more of the plugs may be opened only slightly, so as to throttle the communication of suction to the corresponding filter chamber or chambers.

Likewise, the cracking of wax cakes can be easily controlled by merely cracking a valve, or lust barely opening a plug so as to give the low degree of suction whclch is sunicient to hold the cake on the lter surface but which is insufllcient to cause the undesirable cracking action of the cake.

In the modiiication of Fig. 4, there is illustrated a valve stem 36 of the rising type. In this form, the valve stem is threaded through a threaded opening 55 in the face plate 25'.. The inner end of valve stem 36' isprovided with an extension of smaller diameter carrying a collar 56 l abutting against the shoulder of the larger diameter portion. A sleeve 51 and a threaded collar 58 mounted on the outer threaded end of the smaller diameter portion of the stem complete the assembly. Collars 56 and 58 are mounted within lcircular grooves in opposite faces of plug 35', so

that these collars do not protrude beyond the,

faces of the plug, and the yplug'can be closed tightly-against the wear plate 29' at one end or opened completely against the face plate 25' at the other end. Plug 35' is loosely mounted on collars and sleeve so that as shaft 36 is rotated and moved outwardly to the right as shown in Fig. 4, the plug 35 does not rotate but merely slides along to the right, being guided by the tongue and grooves as previously described. Face plate 25' is provided with an elongated barrel 58' which'loosely receives the threaded portion of stem 36 as it moves to the right through its extreme range of movement, and the outer end of barrel -58' beyond the travel of the threaded portion of stem 3B is equipped with a suitable stuiiing box 31 for sealing the shaft.

In order to make a gas-tight seal between the valve plate-IB and the face plate l1, oil grooves 59 and 8|! (seeFig. 4) are provided in the ends of flanges` 21' and 26' respectively, to which oil under pressure'is supplied by connections BI and 62 respectively. To further hold the face plate snugly against the valve plate, a suction connection 63 is provided at the center oi' the face plate, which forms a partial vacuum in the space 64 between the face plate and the valve plate.

Obviously many variations and modifications of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

.I claim:

l. A continuous rotary drum lter of the character described, comprising in combination, a drum having a peripheral filtering surface and a plurality of separate longitudinally'extending lter chambers formed within the periphery thereof beneath the ltering surface, a hollow journal rotatably supporting said drum, a rotary valve plate carried by said journal adjacent one end thereof, a plurality of pipes extending from said lter chambers through said hollow journal to said valve plate, there being a pipe and an opening therefor through said Valve plate for each of said filter chambers, a stationary face plate abutting against said valve plate and forming an vfithin said cake-forming zone free to communicate with said valve plate openings and without blocking communication of any portion of said annular passage with said fluid connections, said adjustable means being operable from the exterior of said lter without dismantling the same.

2. A continuous rotary drum filter of the character described, comprising in combination, a

drum having a peripheral filtering surface and a plurality of separate longitudinally extending filter chambers formed within the periphery thereof beneath the filtering surface, a hollow journal rotatably supporting said drum, a rotary valve plate carried by said journal adjacent one end thereof, a plurality of pipes extending from said filter chambers through said hollow ljournal to said valve plate, there being a pipe'and an opening therefor through said valve plate for each' of said filter chambers, a stationary face plate abutting against said valve plate and forming an vannular passage provided with iiuid connections adapted to communicate with said openings in the valve plate to provide zones of cake forming, cake Washing and drying, and cake discharge for said filter, and adjustable means for blocking on thevalve plate openings from communication with said annular passage 4in any selected portion or portions of said cake-washing and drying zone while leaving remaining portions of said annular passage within said cake-washing and drying zone free to communicate with said valve plate openings and without blocking communication of any portion of said annular passage with said fluid connectionssaid adjustable means being operable from the exterior of said iilter without dismantling the same.

3. A continuous rotary drum filter' of the character described, comprising in combination, a drum having a peripheraliiltering surface and a plurality of separate longitudinally extending filter chambers formed within the periphery thereof beneath the filtering surface, a hollow journal' rotatably supporting said drum, a rotary valve plate carried by said journal adjacent one end thereof, a plurality of pipes extending from said filter chambers through said hollow journal to said valve plate, there being a pipe and an opening therefor through said valve plate for each of said lter chambers, a stationary" face plate abutting against said valve plate and forming an annular passage provided with uid connections adapted to communicate with said openingsin the valve plate to provide zones of cake forming, cake washing and drying, and cake discharge for 1 said filter, and adjustable means for blocking off the valve plate openings from communication with said annular passage in any selected portion or portions of said cake-forming zone and said cake-washing and drying zone while leaving remaining portions of said annular passage within the said zones free to communicate with said valve plate openings and without blocking vcommunication of any portion of said annular passage with said fluid connections, said adjustable means being operable from the exterior of said filter without dismantling the same.

4. Apparatus according to claim 1, in 'whichi said adjustable means comprises an annular series of positioned plugs, each plug being individuallyv movable between said valve plate and said face plate from a vclosed position adapted to block the pipe openings in the said valve plate as they move opposite said plug to an open position permitting communication between said pipe openings and said annular passage, and an operating shaft for eachof said plugs extending through a stumng box to the exterior of said face plate.

5. In a continuous rotary filter of the type described having a -rotary drum with a peripheral ltering surface anda plurality of segmental longitudinal filtering chambers beneath the nltering surface', together with individual pipe con-fl cumferential series of plugs movably mounted within said fluid chamberI between said plates, and individual means extending to and operable from the exterior of said plates for adjusting each of said plugs from a closed position adapted to block said circumferential series of ports as they move opposite each said plug to an open position permitting communication between said circumferential series of ports and said fluid chamber, each plug being constructed and arranged, to move to a position blocking off an opposed opening in said valve plate while still affording open communication within said iiuid chamber from opposite sides of said plug to said uid connections.

d. Apparatus according to claim 5, in which the plugs are mounted to move in a direction parallel to the longitudinal axis of the nlter, and the individual operating means for each plug comprises a shaft extending longitudinally tllirieugh a stufling box to the exterior of said face p a e.

7. Apparatus according to claim 5, in which the plugs are mounted to move across the width of said fluid chamber and in which each plug has a' thickness less than half the width of the said huid` chamber, whereby when one plug is fully closed and adjacent plugs on opposite sides thereof are fully opened a fluid passage is provided wlithin the uid c ber around the said closed D 11g.

8. In a continuous rotary nlter of the type described having a rotary drum with a peripheral filtering surface and a plurality of segmental longitudinal filtering chambers beneath the nlterlng surface, together with individual pipe connections from said filter chambers to a rotary valve plate carried by the journal of the nlter drum, said valve plate having a circumferential series of ports communicating with-said pipes; a stationary face plate having inwardly extending spaced flanges abutting against said valve plate and forming an annular nuid chamber therebetween, duid connections for said face plate communicating with said annular chamber to provide zones of cake forming, cakewashing and drying. and cake discharge for said fllter, a circumferential series of plugs movably mounted within said annular chamber between said spaced flanges,

individual means extending to and operable from the exterior of said plates for adjusting each of said plligs froml a closed position blocking said circumferential series of-ports to an open position providing communication between said circumferential series of ports and`said annular chamber, and cooperating guiding grooves and tongues between saidenangesfand said' 91u38 for drying, andy cake discharge for said filter', a cirand provided with guiding the said plugs in an adjusting movement. 9. VIn a continuous rotary filter of the typedescribed having a rotary drum with a peripheral filtering surface and a plurality of segmental longitudinal filtering chambers beneath the filtering surface, together with individual pipe connections from said filter chambers to a rotary valve plate carried by the journal ofthe filter drum, said valve plate having a circumferential series of ports communicating with said pipes; a stationary face plate abutting against said valve plate and forming an annular fiuid chamber between said plates opposite said circumferential series of ports, a nonadjustable plug mounted within said annular chamber having` a circum` ferential extent of at least threevalve plate ports a centrally located blow-back connection for cake discharge,A fluid connections communicating with said annular chamber providing zones of cake forming and cake washing and drying, and a circumferential series of individually adjustable plugs mounted within said annular chamber within the cake forming and cake washing and cake drying zones in closely spaced relationship to each other, there being a separate plug for each valve plate port within said zones at any position within ythe cycle of rotation of said valve plate, each adjustable block being movable from a `closed position adapted to block said valve plate ports as they rotate opposite said block to an open position permitting communication between saidvalve plate ports and said annular chamber. i 10. In a continuous rotary filter of the type described having a rotary drum with a peripheral filtering surface and a plurality of segmental longitudinal filtering chambers beneath the filtering surface, together with individual pipe connections from said ilter chambers to a rotary valve plate carried by the journal of the filter drum, said valve plate having a circumferential s'eries of ports communicating with said pipes; a stationary'face plate abutting against said valve plate with spaced flanges between said plates forming an annular uid chamber therebetween and also a central fluid chamber therebetween which is closed from communication with said-` annular fluid chamber, fluid connections communicating with said` annular chamber providing zones of cake forming, cake washing and drying,

and cake discharge for said filter, a circumferential series of plugs moveably mounted within said annular uid chamber for adjustment from a closed position blocking said circumferential series of ports to an opened position providing communication between said circumferential series of ports and said annular fiuid chamber, and a suction connection to said central fluid chamber for producing a partial vacuum therein between said. valve plate and said faceplate.

11. Apparatus according to claim 10, in which abutting portions of said rvalve plate and face plate are provided with liquid sealing grooves, and connections for supplying sealingliquid to said grooves.

12. A continuous rotary drum lter of thev character described, comprising in combination, a

drum having a peripheral filtering surface and a, Vplurality of separate longitudinally extending lter chambers formed within the periphery thereof beneath the filtering surface, a hollow journal rotatably supporting said drum, a rotary Valve plate carried by said journal adjacent'one end thereof, a plurality of pipes extending from ing communication of any portion of said filter chambers through said hollow journal to said valve plate, there being a pipe and an opening therefor through said valve plate for each of said filter chambers, a stationary face plate abutting against said valve plate and having uid connections adapted to communicate with said -openings in the valve plate to` provide zones of' cake forming, cake washing and drying, and cake discharge for said filter, means for rotatably adjusting said base plate relative to said valve plate to thereby adjust the location of said cake forming portion of the filter cycle, and means independent of said adjusting means for blocking 'off said valve plate openings from communication with said vfluid connections within all or any 'selected portion or portions of said cake-forming zone during thero'tation of said valve plate, said blocking off meansbeing operable from the exterior of said filter without dismantling the same.

13. A continuous rotary filter of the character described, comprising in combination, a rotary filter element having a filtering surface and a. series of filter chambers formed within the interior of said element beneath the said filtering surface, valve means rotatable with said filter element having a series of ports communicating with said series of filter chambers, a stationary face plate cooperating with said rotatable valve means forming a fiuid chamber and having fluid connections adapted to communicate through said fluid chamber with said valve ports to provide zones of cakedorming, cake drying and cake discharge for said filter element during rotation thereof, and adjustable means mounted Within said fluid chamber between said valve means and said face plate and operable from the exterior of the filter without dismantling the same for blocking off said valve vports within any selected por'- tion or portionsof the cake forming zone from communication with said fiuid chamber while leavingthe remaining portions oi' said fiuid chamber within the cake forming zone free to communicate with said valve ports and without blocksaid fluid chamber with' said fluid connections.`

14. A continuous rotary drum filter of the character described, comprising in combination, a rotary dr having a peripheral filtering surface and a plurality of separate longitudinally extending filter chambers formed within the drum beneath the said'illtfering surface, valve means rotatable with said drum and having a series of control ports communicating with said filter chambers, a stationary face plate cooperating with'said rotatable valve means forming a uid chamber and having fiuid connections adapted to communicate through said fluid chamber' with said valve ports to provide zones of cake forming, cake drying and cake discharge for said drum filter upon rotation thereof, and adjustable means mounted wiunn said fluid chamber between said valve-means and said face plate and operable from the exterior ofthe lter without dismantling the sanie for blocking o! said valve ports within any selected portion or portions of the cake forming zone from communication with said uid chamber while leaving the remaining portions of said fluid chamber within the lcake forming zone free to communicate with said valve ports and without blocking communication of any portion of said iiuid chamber with said uid connections.

WILLIAM P. GEE. 

